The invention relates generally to direct access storage devices (DASD), and more specifically to air bearing slider structures employed in the head disk assembly (HDA) of a DASD. More particularly, the invention relates to a slider structure which reduces stiction between the air bearing surface of a slider and the surface coating of a rigid disk. Typically, the surface of a rigid disk has applied to it a thin layer of liquid lubricant which serves to reduce friction and potential disk wear when the air bearing surface of a slider contacts the disk surface, as during take-off and landing of the slider.
When a slider is at rest on the surface of a disk, a static frictional force (stiction) between the air bearing surface of a slider and the disk arises from adhesion and from capillary forces exerted primarily by the liquid lubricant. Stiction depends upon the slider/disk contact area, the contact pressure and the thickness of the liquid lubricant layer; it can entirely stall a low torque drive upon startup or cause damage to the disk or slider.
A number of techniques have been proposed for reduction of stiction. For example, some DASD's have been provided with expensive slider load/unload mechanisms. For thin film disks, various means of texturing and patterning the disk surface or slider surface have been proposed and used. While these latter techniques reduce the contact area, they can accelerate disk wear and corrosion and degrade the magnetic signal-to-noise performance of the disk. Large amounts of roughness or texturing can adversely affect slider flying dynamics. Thus, there is an inherent tradeoff between reliability and stiction reduction.
Current slider air bearing designs have been optimized to enhance slider flying dynamics during operation. These designs are variations of a flat air bearing surface (ABS) and generally include a tapered transition between the leading edge of the slider and the flat part of the air bearing surface. The advantage of the transition is that it compresses the air flow under the remaining flat part of the slider's ABS, thereby enhancing the stability and take-off characteristics of the slider during flight. However, these current designs still employ a relatively large flat ABS area and, therefore, do not alleviate the stiction problem.
Accordingly, there is a manifest need for a slider design which reduces stiction. Preferably, such a design would reduce stiction by reducing the slider/disk contact area without reducing device reliability or performance.